Interim Scotland boss Scott Johnson has conceded that Richie Gray looks set for a "significant time away from the game" after he suffered an injury during their 28-18 loss to Wales on Saturday.

Gray was stretchered off during the first-half with a nasty looking hamstring injury and will miss next week's final clash of the championship against France. British & Irish Lions boss Warren Gatland will also be waiting anxiously to find out the nature of Gray's injury as many perceived the Scottish lock to have a good chance of being part of the squad for the summer's tour of Australia.

But Johnson is optimistic that Gray will turn out again this season. "He's in a pretty bad way," Johnson said of Gray's injury. "It's more hamstring but we're not sure of the depth of that. He'll play again this season, I'm sure of that. But it will be a significant time away from the game."

The loss was Scotland's second defeat in this season's championship but Johnson refused to criticise referee Craig Joubert post-match after the South African official dished out an incredible 28 penalties - including a world-record 19 attempts at the posts.

In the end, it was the perceived indiscipline of the hosts at Murrayfield that cost them a 28-18 defeat. Johnson did admit that he was baffled by some of the decisions that went against his team, but the Australian refused to point the finger at the referee as he insisted the reason for the defeat was the fact Scotland failed to make the most of the little ball they had.

Asked about Joubert's numerous interruptions, he said: "It didn't make for a great spectacle. But I'm not here to discuss referees. He's got a job to do and he seems a decent bloke.

"I don't want to be the guy who talks about referees when he loses. The frustrating thing for us is that we had our first line-out in the second half. We think we are a competitive scrum, but we got to play off nothing.

"We let ourselves down but Wales took the most of their opportunities. There is nothing much between those two sides. That bodes well for us because they are world class. But we need to look at ourselves. We can try to find excuses and different reasons why that game didn't go our way. But I'd rather work on what we can do. We can't play Test match rugby like that and we don't want to.

"You score tries off set-piece, but we are not getting set-piece. It's that inability to play off a platform that is stopping us. We had one scrum just before half-time five metres off the line. It was perfect platform to play off. But what happened? We ended up 60 metres back down the track.

"We're always under the cosh. But what we are showing is great resolve. We are defending like mad men. But it would just be nice to have it where we can play a bit."

Engaging too quickly at the scrum was perhaps the most frustrating of the many misdemeanours his side were hauled up for, but Johnson insisted that his side were not trying to pull a fast one. He said: "What frustrates us is that we have a world-class front row. We try to scrum square. We don't teach them any tricks. Our scrum coaches are adamant that's the case. But we are getting nothing from it, and we haven't for three weeks.

"Where we are struggling is that when the referee says set, that's go. But some sides are getting half-cued and not going at all. So there is an illusion that you are going early - when the other mob aren't going. We don't coach that but we have been caught with our pants down a few times."